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Article: Probing the bradycardic drug binding receptor of HCN-encoded pacemaker channels

TitleProbing the bradycardic drug binding receptor of HCN-encoded pacemaker channels
Authors
KeywordsDrug
HCN
Inner pore
Pacemaker channels
ZD7288
Issue Date2009
PublisherSpringer. The Journal's web site is located at http://link.springer.de/link/service/journals/00424/index.htm
Citation
Pflugers Archiv European Journal Of Physiology, 2009, v. 459 n. 1, p. 25-38 How to Cite?
AbstractIf- (or Ih), encoded by the hyperpolarizationactivated, cyclic nucleotide-gated (HCN1-4) channel gene family, contributes significantly to cardiac pacing. Bradycardia agents such as ZD7288 that target HCN channels have been developed, but the molecular configuration of their receptor is poorly defined. Here, we probed the drug receptor by systematically introducing alanine scanning substitutions into the selectivity filter (C347A, I348A, G349A, Y350A, G351A in the P-loop), outer (P355A, V356A, S357A, M358A in the P-S6 linker), and inner (M377A, F378A, V379A in S6) pore vestibules of HCN1 channels. When heterologously expressed in human embryonic kidney 293 cells for patch-clamp recordings, I348A, G349A, Y350A, G351A, P355A, and V356A did not produce measurable currents. The half-blocking concentration (IC50) of wild type (WT) for ZD7288 was 25.8± 9.7 μM. While the IC50 of M358A was identical to WT, those of C347A, S357A, F378A, and V379A markedly increased to 137.6±56.4, 113.3±34.1, 587.1±167.5, and 1726.3±673.4 μM, respectively (p<0.05). Despite the proximity of the S6 residues studied, M377A was hypersensitive (IC50=5.1±0.7 μM; p<0.05) implicating site specificity. To explore the energetic interactions among the S6 residues, double and triple substitutions (M377A/ F378A, M377A/V379A, F378A/V379A, and M377A/ F378A/V379A) were generated for thennodynamic cycle analysis. Specific interactions with coupling energies (ΔΔG) >1 kT for M377-F378 and F378-V379 but not M377-V379 were identified. Based on these new data and others, we proposed a refined drug-blocking model that may lead to improved antiarrhythmics and bioartificial pacemaker designs.
Persistent Identifierhttp://hdl.handle.net/10722/144954
ISSN
2015 Impact Factor: 3.654
2015 SCImago Journal Rankings: 1.638
PubMed Central ID
ISI Accession Number ID
Funding AgencyGrant Number
NIHR01 HL72857
University of California, Davis School of Medicine
Hong Kong Research7459/04M
CC Wong Stem Cell Fund
Funding Information:

This work was supported by grants from the NIH (R01 HL72857 to RAL), the Stem Cell Program of the University of California, Davis School of Medicine (to RAL), the Hong Kong Research Grant Council (7459/04M to CPL, HFT, and RAL), and the CC Wong Stem Cell Fund (to HFT and RAL).

References

 

DC FieldValueLanguage
dc.contributor.authorChan, YCen_HK
dc.contributor.authorWang, Ken_HK
dc.contributor.authorAu, KWen_HK
dc.contributor.authorLau, CPen_HK
dc.contributor.authorTse, HFen_HK
dc.contributor.authorLi, RAen_HK
dc.date.accessioned2012-02-21T05:44:52Z-
dc.date.available2012-02-21T05:44:52Z-
dc.date.issued2009en_HK
dc.identifier.citationPflugers Archiv European Journal Of Physiology, 2009, v. 459 n. 1, p. 25-38en_HK
dc.identifier.issn0031-6768en_HK
dc.identifier.urihttp://hdl.handle.net/10722/144954-
dc.description.abstractIf- (or Ih), encoded by the hyperpolarizationactivated, cyclic nucleotide-gated (HCN1-4) channel gene family, contributes significantly to cardiac pacing. Bradycardia agents such as ZD7288 that target HCN channels have been developed, but the molecular configuration of their receptor is poorly defined. Here, we probed the drug receptor by systematically introducing alanine scanning substitutions into the selectivity filter (C347A, I348A, G349A, Y350A, G351A in the P-loop), outer (P355A, V356A, S357A, M358A in the P-S6 linker), and inner (M377A, F378A, V379A in S6) pore vestibules of HCN1 channels. When heterologously expressed in human embryonic kidney 293 cells for patch-clamp recordings, I348A, G349A, Y350A, G351A, P355A, and V356A did not produce measurable currents. The half-blocking concentration (IC50) of wild type (WT) for ZD7288 was 25.8± 9.7 μM. While the IC50 of M358A was identical to WT, those of C347A, S357A, F378A, and V379A markedly increased to 137.6±56.4, 113.3±34.1, 587.1±167.5, and 1726.3±673.4 μM, respectively (p<0.05). Despite the proximity of the S6 residues studied, M377A was hypersensitive (IC50=5.1±0.7 μM; p<0.05) implicating site specificity. To explore the energetic interactions among the S6 residues, double and triple substitutions (M377A/ F378A, M377A/V379A, F378A/V379A, and M377A/ F378A/V379A) were generated for thennodynamic cycle analysis. Specific interactions with coupling energies (ΔΔG) >1 kT for M377-F378 and F378-V379 but not M377-V379 were identified. Based on these new data and others, we proposed a refined drug-blocking model that may lead to improved antiarrhythmics and bioartificial pacemaker designs.en_HK
dc.languageengen_US
dc.publisherSpringer. The Journal's web site is located at http://link.springer.de/link/service/journals/00424/index.htmen_HK
dc.relation.ispartofPflugers Archiv European Journal of Physiologyen_HK
dc.rightsThe Author(s)en_US
dc.rightsCreative Commons: Attribution 3.0 Hong Kong Licenseen_US
dc.subjectDrugen_HK
dc.subjectHCNen_HK
dc.subjectInner poreen_HK
dc.subjectPacemaker channelsen_HK
dc.subjectZD7288en_HK
dc.subject.meshCardiotonic Agents - pharmacology-
dc.subject.meshCyclic Nucleotide-Gated Cation Channels - chemistry - metabolism-
dc.subject.meshPotassium Channels - chemistry - metabolism-
dc.subject.meshProtein Structure, Quaternary - drug effects-
dc.subject.meshPyrimidines - pharmacology-
dc.titleProbing the bradycardic drug binding receptor of HCN-encoded pacemaker channelsen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4551/resserv?sid=springerlink&genre=article&atitle=Probing the bradycardic drug binding receptor of HCN-encoded pacemaker channels&title=Pflügers Archiv European Journal of Physiology&issn=00316768&date=2009-11-01&volume=459&issue=1& spage=25&authors=Yau-Chi Chan, Kai Wang, Ka Wing Au, <i>et al.</i>en_US
dc.identifier.emailChan, YC:yauchi@graduate.hku.hken_HK
dc.identifier.emailTse, HF:hftse@hkucc.hku.hken_HK
dc.identifier.emailLi, RA:ronaldli@hkucc.hku.hken_HK
dc.identifier.authorityChan, YC=rp01502en_HK
dc.identifier.authorityTse, HF=rp00428en_HK
dc.identifier.authorityLi, RA=rp01352en_HK
dc.description.naturepublished_or_final_versionen_US
dc.identifier.doi10.1007/s00424-009-0719-2en_HK
dc.identifier.pmid19756722en_HK
dc.identifier.pmcidPMC2765624-
dc.identifier.scopuseid_2-s2.0-73949145500en_HK
dc.identifier.hkuros157408-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-73949145500&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume459en_HK
dc.identifier.issue1en_HK
dc.identifier.spage25en_HK
dc.identifier.epage38en_HK
dc.identifier.eissn1432-2013en_US
dc.identifier.isiWOS:000271028700003-
dc.publisher.placeGermanyen_HK
dc.description.otherSpringer Open Choice, 21 Feb 2012en_US
dc.identifier.scopusauthoridChan, YC=7403676116en_HK
dc.identifier.scopusauthoridWang, K=35286098800en_HK
dc.identifier.scopusauthoridAu, KW=9738204200en_HK
dc.identifier.scopusauthoridLau, CP=7401968501en_HK
dc.identifier.scopusauthoridTse, HF=7006070805en_HK
dc.identifier.scopusauthoridLi, RA=7404724466en_HK
dc.identifier.citeulike5815401-

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